150 research outputs found

    The dynamical tides of spinning Newtonian stars

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    We carefully develop the framework required to model the dynamical tidal response of a spinning neutron star in an inspiralling binary system, in the context of Newtonian gravity, making sure to include all relevant details and connections to the existing literature. The tidal perturbation is decomposed in terms of the normal oscillation modes, used to derive an expression for the effective Love number which is valid for any rotation rate. In contrast to previous work on the problem, our analysis highlights subtle issues relating to the orthogonality condition required for the mode-sum representation of the dynamical tide and shows how the prograde and retrograde modes combine to provide the overall tidal response. Utilising a slow-rotation expansion, we show that the dynamical tide (the effective Love number) is corrected at first order in rotation, whereas in the case of the static tide (the static Love number) the rotational corrections do not enter until second order.PP acknowledges support from the María Zambrano Fellowship Programme (ZAMBRANO21), funded by the Spanish Ministry of Universities and the University of Alicante through the European Union’s “Next Generation EU” package, as well as from the grant PID2021-127495NBI00, funded by MCIN/AEI/10.13039/501100011033 and by the European Union, from the Astrophysics and High Energy Physics programme of the Generalitat Valenciana ASFAE/2022/026, funded by the Spanish Ministry of Science and Innovation (MCIN) and the European Union’s “Next Generation EU” package (PRTR-C17.I1), and from the Prometeo 2023 excellence programme grant CIPROM/2022/13, funded by the Ministry of Innovation, Universities, Science, and Digital Society of the Generalitat Valenciana. This work was also supported by the “Ministero dell’istruzione, dell’università e della ricerca" (MIUR) PRIN 2017 programme (CUP: B88D19001440001), from the Amaldi Research Center, funded by the MIUR programme “Dipartimento di Eccellenza" (CUP: B81I18001170001), and from the EU Horizon 2020 Research and Innovation Programme under the Marie Skłodowska-Curie Grant Agreement N. 101007855. FG, NA, and DIJ are grateful for support from STFC via grant numbers ST/R00045X/1 and ST/V000551/1

    The rotational modes of relativistic stars: Numerical results

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    We study the inertial modes of slowly rotating, fully relativistic compact stars. The equations that govern perturbations of both barotropic and non-barotropic models are discussed, but we present numerical results only for the barotropic case. For barotropic stars all inertial modes are a hybrid mixture of axial and polar perturbations. We use a spectral method to solve for such modes of various polytropic models. Our main attention is on modes that can be driven unstable by the emission of gravitational waves. Hence, we calculate the gravitational-wave growth timescale for these unstable modes and compare the results to previous estimates obtained in Newtonian gravity (i.e. using post-Newtonian radiation formulas). We find that the inertial modes are slightly stabilized by relativistic effects, but that previous conclusions concerning eg. the unstable r-modes remain essentially unaltered when the problem is studied in full general relativity.Comment: RevTeX, 29 pages, 31 eps figure

    A consistent first-order model for relativistic heat flow

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    This paper revisits the problem of heat conduction in relativistic fluids, associated with issues concerning both stability and causality. It has long been known that the problem requires information involving second order deviations from thermal equilibrium. Basically, any consistent first-order theory needs to remain cognizant of its higher-order origins. We demonstrate this by carrying out the required first-order reduction of a recent variational model. We provide an analysis of the dynamics of the system, obtaining the conditions that must be satisfied in order to avoid instabilities and acausal signal propagation. The results demonstrate, beyond any reasonable doubt, that the model has all the features one would expect of a real physical system. In particular, we highlight the presence of a second sound for heat in the appropriate limit. We also make contact with previous work on the problem by showing how the various constraints on our system agree with previously established results.Comment: RevTeX, 1 eps Figur

    Cost-effectiveness of internet-based cognitive behavior therapy for irritable bowel syndrome: results from a randomized controlled trial

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    Background: Irritable Bowel Syndrome (IBS) is highly prevalent and is associated with a substantial economic burden. Cognitive behavior therapy (CBT) has been shown to be effective in treating IBS. The aim of this study was to evaluate the cost-effectiveness of a new treatment alternative, internet-delivered CBT based on exposure and mindfulness exercises. Methods: Participants (N = 85) with IBS were recruited through self-referral and were assessed via a telephone interview and self-report measures on the internet. Participants were randomized to internet-delivered CBT or to a discussion forum. Economic data was assessed at pre-, post- and at 3-month and 1 year follow-up. Results: Significant cost reductions were found for the treatment group at $16,806 per successfully treated case. The cost reductions were mainly driven by reduced work loss in the treatment group. Results were sustained at 3-month and 1 year follow-up. Conclusions: Internet-delivered CBT appears to generate health gains in IBS treatment and is associated with cost-savings from a societal perspective.Original Publication:Erik Andersson, Brjann Ljotsson, Filip Smit, Björn Paxling, Erik Hedman, Nils Lindefors, Gerhard Andersson and Christian Ruck, Cost-effectiveness of internet-based cognitive behavior therapy for irritable bowel syndrome: results from a randomized controlled trial, 2011, BMC PUBLIC HEALTH, (11), 215.http://dx.doi.org/10.1186/1471-2458-11-215Licensee: BioMed Centralhttp://www.biomedcentral.com

    Sensory Ataxic Neuropathy in Golden Retriever Dogs Is Caused by a Deletion in the Mitochondrial tRNATyr Gene

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    Sensory ataxic neuropathy (SAN) is a recently identified neurological disorder in golden retrievers. Pedigree analysis revealed that all affected dogs belong to one maternal lineage, and a statistical analysis showed that the disorder has a mitochondrial origin. A one base pair deletion in the mitochondrial tRNATyr gene was identified at position 5304 in affected dogs after re-sequencing the complete mitochondrial genome of seven individuals. The deletion was not found among dogs representing 18 different breeds or in six wolves, ruling out this as a common polymorphism. The mutation could be traced back to a common ancestor of all affected dogs that lived in the 1970s. We used a quantitative oligonucleotide ligation assay to establish the degree of heteroplasmy in blood and tissue samples from affected dogs and controls. Affected dogs and their first to fourth degree relatives had 0–11% wild-type (wt) sequence, while more distant relatives ranged between 5% and 60% wt sequence and all unrelated golden retrievers had 100% wt sequence. Northern blot analysis showed that tRNATyr had a 10-fold lower steady-state level in affected dogs compared with controls. Four out of five affected dogs showed decreases in mitochondrial ATP production rates and respiratory chain enzyme activities together with morphological alterations in muscle tissue, resembling the changes reported in human mitochondrial pathology. Altogether, these results provide conclusive evidence that the deletion in the mitochondrial tRNATyr gene is the causative mutation for SAN

    Internet-based cognitive behavior therapy for obsessive compulsive disorder: A pilot study

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    <p>Abstract</p> <p>Background</p> <p>Cognitive behavior therapy (CBT) is widely regarded as an effective treatment for obsessive compulsive disorder (OCD), but access to CBT therapists is limited. Internet-based CBT (ICBT) with therapist support is a way to increase access to CBT but has not been developed or tested for OCD. The aim of this study was to evaluate ICBT for OCD.</p> <p>Method</p> <p>An open trial where patients (N = 23) received a 15-week ICBT program with therapist support consisting of psychoeducation, cognitive restructuring and exposure with response prevention. The primary outcome was the Yale-Brown Obsessive Compulsive Scale (Y-BOCS), which was assessed by a psychiatrist before and immediately after treatment. Secondary outcomes were self-rated measures of OCD symptoms, depressive symptoms, general functioning, anxiety and quality of life. All assessments were made at baseline and post-treatment.</p> <p>Results</p> <p>All participants completed the primary outcome measure at all assessment points. There were reductions in OCD symptoms with a large within-group effect size (Cohen's <it>d </it>= 1.56). At post-treatment, 61% of participants had a clinically significant improvement and 43% no longer fulfilled the diagnostic criteria of OCD. The treatment also resulted in statistically significant improvements in self-rated OCD symptoms, general functioning and depression.</p> <p>Conclusions</p> <p>ICBT with therapist support reduces OCD symptoms, depressive symptoms and improves general functioning. Randomized trials are needed to confirm the effectiveness of this new treatment format.</p> <p>Trial Registration</p> <p>ClinicalTrials.gov: <a href="http://www.clinicaltrials.gov/ct2/show/NCT01348529">NCT01348529</a></p

    Revealing hidden species distribution with pheromones: the case of Synanthedon vespiformis (Lepidoptera: Sesiidae) in Sweden

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    Synanthedon vespiformis L. (Lepidoptera: Sesiidae) is considered a rare insect in Sweden, discovered in 1860, with only a few observations recorded until a sex pheromone attractant became available recently. This study details a national survey conducted using pheromones as a sampling method for this species. Through pheromone trapping we captured 439 specimens in Southern Sweden at 77 sites, almost tripling the number of previously reported records for this species. The results suggest that S. vespiformis is truly a rare species with a genuinely scattered distribution, but can be locally abundant. Habitat analyses were conducted in order to test the relationship between habitat quality and the number of individuals caught. In Sweden, S. vespiformis is thought to be associated with oak hosts, but our attempts to predict its occurrence by the abundance of oaks yielded no significant relationships. We therefore suggest that sampling bias and limited knowledge on distribution may have led to the assumption that this species is primarily reliant on oaks in the northern part of its range, whereas it may in fact be polyphagous, similar to S. vespiformis found as an agricultural pest in Central and Southern Europe. We conclude that pheromones can massively enhance sampling potential for this and other rare lepidopteran species. Large-scale pheromone-based surveys provide a snapshot of true presences and absences across a considerable part of a species national distribution range, and thus for the first time provide a viable means of systematically assessing changes in distribution over time with high spatiotemporal resolution

    Therapygenetic effects of 5-HTTLPR on cognitive-behavioral therapy in anxiety disorders: a meta-analysis

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    There is a recurring debate on the role of the serotonin transporter gene linked polymorphic region (5-HTTLPR) in the moderation of response to cognitive behavioral therapy (CBT) in anxiety disorders. Results, however, are still inconclusive. We here aim to perform a meta-analysis on the role of 5-HTTLPR in the moderation of CBT outcome in anxiety disorders. We investigated both categorical (symptom reduction of at least 50%) and dimensional outcomes from baseline to post-treatment and follow-up. Original data were obtained from ten independent samples (including three unpublished samples) with a total of 2,195 patients with primary anxiety disorder. No significant effects of 5-HTTLPR genotype on categorical or dimensional outcomes at post and follow-up were detected. We conclude that current evidence does not support the hypothesis of 5-HTTLPR as a moderator of treatment outcome for CBT in anxiety disorders. Future research should address whether other factors such as long-term changes or epigenetic processes may explain further variance in these complex gene-environment interactions and molecular-genetic pathways that may confer behavioral change following psychotherapy
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